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부산지역 도시하천 표층 퇴적물 오염도 평가에 관한 연구
곽진숙 ( Jin-suk Kwag ),손정원 ( Jung-won Son ),김주인 ( Chu-In Kim ),송복주 ( Bok-Joo Song ) 한국물환경학회(구 한국수질보전학회) 2021 한국물환경학회지 Vol.37 No.4
This work investigated heavy metal pollution in surface sediments of rivers in Busan, Korea. Surface sediments were analyzed in order to conduct contamination assessment of organic matter, nutrients, and heavy metal concentrations. Contamination assessment of heavy metals was conducted using geoaccumulation index (I<sub>geo</sub>), pollution load index (PLI), and potential ecological risk index (RI). Accumulation of organic matter and nutrients were affected by water discharged from sewage treatment plant. The concentrations of organic matter and nutrients were found to be greater in points which were close to the sewage treatment plant more than points furthest. The concentrations of Pb, Zn, Cu, Cd, Hg, As, Cr, and Ni were found to be greater in surface sediment more than in the background. The mean concentrations of heavy metals were in the order of Zn (323.5 mg/kg) > Cu (70.5 mg/kg) > Pb (39.8 mg/kg) > Cr (33.4 mg/kg) > Ni (13.5 mg/kg) > As (9.4 mg/kg) > Cd (0.84 mg/kg) > Hg (0.092 mg/kg). The result of geoaccumulation indices indicated that Hg > Cr > Cu > Ni > Zn > As > Pb > Cd were found in order of severe contamination by heavy metals. From PLI and RI analysis, it was evident that the Suyeonggang 2 was the most contaminated river.
김상현,박남식,김주인,정봉석,도중호 대한상하수도학회 2001 상하수도학회지 Vol.15 No.3
The characteristics of unsteady pipe flow to an external impact such as valve modulation can be detected in a frequency domain. Fast Fourier Transformation is employed to convert the head variation in the time domain to the amplitude of the frequency domain. Application of the method of characteristics to a pipeline provides a range of frequency representing a particular unsteady condition. Inverse Fast Fourier Transformation and a Finite Impulse Response Filter can be used to remove noise present in the frequency range. Characteristics of the frequency range for various conditions such as valve modulation and a minor modification of a pipeline are explored to demonstrate the effectiveness of the noise control method in the frequency domain. A noise contaminated signal was successfully filtered using a low pass filter, which was designed from a frequency analysis of head variation.